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Physics and astronomy thread (2 Viewers)

Phil Elliott said:
"While this is not the 'hole-in-one' we hoped for, there is always risk with breaking new ground,"

Literally and figuratively.
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Rock sample was far more brittle than anticipated apparently, and just disintegrated. I'm actually less confident in this side of the experiments in terms of retrieval- even if they successfully extract a sample.

But enough of that...cool video from the 11th flight showing Percy in the distance.

 
Flight 12 info...

__________________

The chopper is eyeing a region called South Seitah, an area that's home to boulders and rocky outcrops that are of interest to the Perseverance rover team. "This flight will be ambitious. Flying over Seitah South carries substantial risk because of the varied terrain," Ingenuity team lead Teddy Tzanetos wrote in a status update on Sunday.   

The helicopter's navigation system was designed to work with relatively flat terrain, so making sense out of rougher landscapes can be a challenge. The rotorcraft has run into some technical difficulties, but survived them all so far.

Ingenuity's flight was targeted for early Monday, but it can take time to get confirmation of the flight back from Mars.  

If all goes well, Perseverance will meet up with Ingenuity in the coming days. The helicopter's reconnaissance work should help the rover team decide what spots to check out once it's there.

Ingenuity as a mission has been all about risks and rewards. It was an unknown whether the helicopter would even work on Mars. It not only works, it's also showing how an aerial vehicle can act as a valuable scout for a ground-based rover. 

"When we choose to accept the risks associated with such a flight, it is because of the correspondingly high rewards," Tzanetos said. "Knowing that we have the opportunity to help the Perseverance team with science planning by providing unique aerial footage is all the motivation needed.

 
I wonder if a mission of multiple rotorcraft with science instruments and a simple base station for landing and comms would work... weight on the rotorcraft payload would be critical.

 
Jupiter and 4 moons

Had a great view tonight.

Not a great photo - trying to line-up the phone is difficult.  And I don't have the telescope on auto tracker, so if I user a higher magnification lens it moves through the view too quickly and blurs everything.  

Saturn was up tonight also - and I am never not amazed at seeing the rings so crisply.  Alas, those photos were even worse!

 
Sinn Fein said:
Jupiter and 4 moons

Had a great view tonight.

Not a great photo - trying to line-up the phone is difficult.  And I don't have the telescope on auto tracker, so if I user a higher magnification lens it moves through the view too quickly and blurs everything.  

Saturn was up tonight also - and I am never not amazed at seeing the rings so crisply.  Alas, those photos were even worse!
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Nice dude! What telescope you using? 

 
The Gator said:
Nice dude! What telescope you using? 
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I ended up getting the Celestron NextStar 8SE 

It has the computerized GoTo mount, but I have never taken the time to learn how properly align it, hence no auto-tracking.  I am still pretty much looking at objects that I know...

Maybe this fall< I learn how to get it aligned, and then next year or two a camera attachment.

 
Ginny should be attempting flight 14 very soon (maybe even today). It's been there so long, the atmospheric conditions have changed becoming more dense- beyond what it had originally been designed for.

This flight will be a test flight, spinning it's rotors faster to accommodate the new conditions. Fingers crossed...a lot can wrong as a result of this.

 
El Floppo said:
Ginny should be attempting flight 14 very soon (maybe even today). It's been there so long, the atmospheric conditions have changed becoming more dense- beyond what it had originally been designed for.

This flight will be a test flight, spinning it's rotors faster to accommodate the new conditions. Fingers crossed...a lot can wrong as a result of this.
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One would think that the rotors would spin slower as the atmospheric density goes up. 

 
The Z Machine said:
One would think that the rotors would spin slower as the atmospheric density goes up. 
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Fwiw...

________________

When we designed and tested Ingenuity on Earth, we expected Ingenuity’s five-flight mission to be completed within the first few months after Perseverance’s landing in February 2021. We therefore prepared for flights at atmospheric densities between 0.0145 and 0.0185 kg/m3, which is equivalent to 1.2-1.5% of Earth’s atmospheric density at sea level. With Ingenuity in its sixth month of operation, however, we have entered a season where the densities in Jezero Crater are dropping to even lower levels. In the coming months we may see densities as low as 0.012 kg/m3 (1.0% of Earth’s density) during the afternoon hours that are preferable for flight.

The difference may seem small, but it has a significant impact on Ingenuity’s ability to fly. At our lower design limit for atmospheric density (0.0145 kg/m3), we know that Ingenuity has a thrust margin of at least 30%. Thrust margin refers to the excess thrust that Ingenuity can produce above and beyond what is required to hover. That additional thrust is needed on takeoffs and climbs, during maneuvers, and also when tracking terrain with varying height. But if the atmospheric density were to drop to 0.012 kg/m3 in the coming months, our helicopter’s thrust margin could drop to as low as 8%, which means that Ingenuity would be operating close to aerodynamic stall (a condition where further increases in the blade’s angle of attack does not produce more lift, only more drag).

Thankfully, there is a way to tackle this issue – but it involves spinning the rotors even faster than we have been doing up to now. In fact, they will have to spin faster than we have ever attempted with Ingenuity or any of our test helicopters on Earth. This is not something we take lightly, which is why our next operations on Mars will be focused on carefully testing out higher rotor speeds in preparation for future flights.

We will begin by performing a high-speed spin of the rotor without leaving the ground, reaching a peak rotor speed of 2,800 rpm (more than a 10% increase relative to our prior Mars experience of 2,537 rpm). If all goes well, we will follow this with a short test flight at a slightly lower rotor speed of 2,700 rpm. This would be our 14th flight and (hopefully) a relatively boring one compared to any of our more recent flights, where we flew long distances to acquire images of interest for the Perseverance rover team. Occurring no earlier than Friday, Sept. 17 (with data coming down no earlier than Saturday morning), the short hop would have Ingenuity take off, climb to 16 feet (5 meters), perform a small translation (sideways move), and then land again. And while the results from a Flight 14 should be less than riveting, the significant increase in available rpms (from 2,537 to 2,700) for future helicopter operations will provide us the option to perform scouting missions for Perseverance at lower atmospheric densities. It also leaves some wiggle room if we decide an additional rpm increase is needed later.

A speed increase like this comes with a number of potential issues. One of these has to do with aerodynamics: A rotor speed of 2,800 rpm, in combination with wind and helicopter motion, could cause the tips of the rotor blades to encounter the air at nearly 0.8 Mach – that is, 80% of the speed of sound on Mars. (The speed of sound on Mars is somewhat lower than we are used to – about ¾ the speed of sound on Earth.) If the blade tips get sufficiently close to the speed of sound, they will experience a very large increase in aerodynamic drag that would be prohibitive for flight. For Ingenuity’s rotor we do not expect to encounter this phenomenon until even higher Mach numbers, but this has never been confirmed in testing on Earth.

Another potential issue is unknown resonances in the helicopter structure. Like all mechanical systems, Ingenuity has resonances that can lead to large vibrations when excited at particular frequencies. It is important to ensure that there are no significant resonances at the rotor speed used for flight, as this could cause damage to hardware and lead to a deterioration in sensor readings needed by the flight control system.

Additional demands will also be put on several components of Ingenuity’s design: The motors will need to spin faster, the electrical system will need to deliver more power, and the entire rotor system will need to withstand the higher loads that come with increased rotor speeds. It all adds up to a significant challenge, but by approaching the issue slowly and methodically, we hope to fully check out the system at higher rotor speeds and enable Ingenuity to keep flying in the months ahead. Stay tuned for updates.

 
So this article (it's deep) goes into the destruction of Tall El-Hammam (which is near Jericho) by a Tunguska like blast.  My place of work contributed by doing high rate heating tests of pottery to compare up against the as-found artifacts.

 
I saw the thread bumped and was hoping Ginny flew again or that the Chinese rover did something cool.  

But nice work on the hot pottery. 🙃

For real though, getting something into Nature is no joke. 

 
The Z Machine said:
I saw the thread bumped and was hoping Ginny flew again
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Fwiw...

_____________________

Ingenuity performed a high-speed rotation test on Sept. 15, spinning its blades at 2,800 RPM for a spell while it remained on the ground. Everything went well, paving the way for the Sept. 18 flight. But the 4-pound (1.8 kilograms) chopper did not end up taking off that day.

"Here's what happened: Ingenuity detected an anomaly in two of the small flight-control servo motors (or simply 'servos') during its automatic pre-flight checkout and did exactly what it was supposed to do: It canceled the flight," Karras wrote.

Ingenuity has six servos, three for each of its two rotors. The little motors adjust the pitch of the rotors, allowing the chopper to control its orientation and position during flight.

"The servo motors are much smaller than the motors that spin the rotors, but they do a tremendous amount of work and are critical to stable, controlled flight," Karras wrote.

Analysis of the Sept. 18 preflight test has shown that two of Ingenuity's servos oscillated slightly during the "servo wiggle" checkout. The team is still trying to determine the cause, but it may be due to increasing wear in the servo gearboxes and linkages, Karras wrote. (Ingenuity is a technology demonstrator that was originally supposed to make just five flights on the Red Planet.)

Ingenuity passed two additional servo wiggle tests on Sept. 21 and Sept. 23, however, "so the issue isn’t entirely repeatable," Karras wrote. "We have a number of tools available for working through the anomaly, and we're optimistic that we'll get past it and back to flying again soon."

But orbital dynamics will keep Ingenuity grounded for a couple more weeks at least. Mars is now in "solar conjunction," meaning it's on the other side of the sun from Earth. Our star can corrupt and otherwise interfere with communications sent between the two planets, so NASA has stopped sending commands to Ingenuity and its other Red Planet robots — including Ingenuity's much larger partner, the Perseverance rover— until mid-October, when Mars will come more clearly into view.

"Ingenuity will not be completely idle during this time, however; Ingenuity and Perseverance will be configured to keep each other company by communicating roughly once a week, with Ingenuity sending basic system health information to its base station on Perseverance," Karras wrote. "We will receive this data on Earth once we come out of conjunction, and will learn how Ingenuity performs over an extended period of relative inactivity on Mars. See you on the other side of conjunction!"

 
The Z Machine said:
I saw the thread bumped and was hoping Ginny flew again or that the Chinese rover did something cool.  

But nice work on the hot pottery. 🙃

For real though, getting something into Nature is no joke. 
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Damnit, where is that finger emoji when you really need it?   :lol:

 
Sinn Fein said:
I ended up getting the Celestron NextStar 8SE 

It has the computerized GoTo mount, but I have never taken the time to learn how properly align it, hence no auto-tracking.  I am still pretty much looking at objects that I know...

Maybe this fall< I learn how to get it aligned, and then next year or two a camera attachment.
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My kids are super interested in space and astronomy.  What is the best telescope and way to cultivate this as a hobby for us to do together?

Bad thing is that I have pretty bad light pollution here.

 
Leeroy Jenkins said:
My kids are super interested in space and astronomy.  What is the best telescope and way to cultivate this as a hobby for us to do together?

Bad thing is that I have pretty bad light pollution here.
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https://www.space.com/15693-telescopes-beginners-telescope-reviews-buying-guide.html

This is kind of where I started looking around, and learning about the various types of telescopes.  Not sure where you are - but light pollution should not be a big deal for a lot of things you can see in the night sky.  It will impact some of the simmer objects

 
El Floppo said:
Ginny flight #14 is in the books and a success!

Just an up and down test flight with higher RPMs to combat the change in seasonal air density. Now that the higher RPMs work, they should be able to get back in action to scout for Percy.

Speaking of Percy- latest pics

Both were shut down the last weeks because Mars was behind the sun, unable to be contacted from Earth.
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Flight 15 a success!

__________

Ingenuity completed its 15th overall flight on Mars, flying 128.8 seconds and about 400 meters across the surface of Mars. This flight proves that Ingenuity is capable of flying on Mars even in the thinnest atmosphere and sets the stage for future low-density-atmosphere scouting missions to check out scientifically interesting areas.

Cumulatively, Ingenuity has now flown more than 3 km across the surface of Mars—more than five times farther than NASA had hoped to demonstrate with this technology. It's safe to say that flying on other worlds, with atmospheres, will be more than just a passing fad for future exploratory missions. Rather, it likely represents the future.

 
El Floppo said:
Cumulatively, Ingenuity has now flown more than 3 km across the surface of Mars—more than five times farther than NASA had hoped to demonstrate with this technology. It's safe to say that flying on other worlds, with atmospheres, will be more than just a passing fad for future exploratory missions. Rather, it likely represents the future.
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So cool. 

I wonder how far the Mars rovers have traveled cumulatively?

 
El Floppo said:
Cumulatively, Ingenuity has now flown more than 3 km across the surface of Mars—more than five times farther than NASA had hoped to demonstrate with this technology. It's safe to say that flying on other worlds, with atmospheres, will be more than just a passing fad for future exploratory missions. Rather, it likely represents the future.
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:boner:

 
Sinn Fein said:
It really is amazing that she is still flying, given the different atmospheric conditions, the general wear and tear from flight and landings, and dust conditions, just generally, and from take-offs/landings.
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:goodposting:

That they got one flight in...let alone 15 and counting...amazing. So many things could go wrong- from wind gusts to just landing on a rock and tipping over, let alone all of the myriad programming and technical issues as you point out.

And it went so quickly from proof of concept into full blown operational tool...I genuinely have my breath taken away when I see these photos and videos.

 
she's flying so much I completely missed #16.

but 17 is in the books for Ginny on Dec 5th. they apparently had some telemetry issues- this time she went up 33' and to the NE 600+', but lost radio contact with Percy when she dropped behind a rock outcropping on her descent. but supposedly everything went perfectly (although they're still receiving data).

#18 upcoming in the next week or two.

considering this was all just supposed to be a proof of concept experiment with a hoped for 5 flights... it's all pretty incredible.

 
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